How did he die?

Situation puzzles (sometimes called lateral thinking puzzles) are ones where you need to ask lots of yes or no questions to figure out what happened in the situation. These are good puzzles for groups where one person knows the puzzle and answers the questions.

A man and his wife are eating a meal in a cabin. They finish their food. The wife asks him if he would like some coffee. He says `yes`, and she gives him some. After he finishes his beverage, he excuses himself to use the restroom. Afterwards, instead of returning to his wife, he decides to go outside for some fresh air. Upon seeing this, the wife becomes hysterical and cries about the death of her husband. How did he die?